DIFFERENTIAL REGULATION OF THE FORMATION OF PROSTAGLANDINS AND RELATED SUBSTANCES FROM ARACHIDONIC-ACID AND FROM DIHOMOGAMMALINOLENIC ACID .2. EFFECTS OF VITAMIN-C

Vitamin C over the concentration range 10 to 100 pg/ml (5.7-57 x 10-5 M) caused a dose dependent and highly significant enhancement of conversion of 14C-dihomogamnalinolenic acid (DGLA) to prostaglandin (PG) El and to thromboxane (Tx) BI by human platelets. Vitamin C had no effect on conversion of 14C-arachidonic acid to PGE2 and TxB2. The concentration range is relevant to physiology: in some cells which concentrate the vitamin, such as polymorphonuclear leucocytes and the adrenal cortex, vitamin C concentrations may be substantially higher than 100 μg/ml. Vitamin C can therefore selectively enhance the formation of cyclo-oxygenase generated products from DGLA without changing formation of those from AA. This effect can account for a number of the known actions of vitamin C including its effect on the immune system. The implications of this finding are discussed. © 1979.